For a simulated experience with respect to driving airplanes, automobiles, motorcycles, bicycles and the like, simulation systems corresponding to the respective vehicles have been proposed. Some of these devises have been put to practical use. In a bicycle simulation system, the rider (operator) operates pedals while being seated astride a saddle of a dummy bicycle to thereby perform a simulated cycling, a simulated velocity and the like are obtained by detecting the rotation of the pedals by a predetermined speed sensor, and a simulation process is executed.
The dummy bicycle used in the bicycle simulation system may be provided with a flywheel for giving an appropriate load to the rotation of the pedals. See, for example, Japanese Patent Publication No. Hei 6-7873.
The form of utilization of a bicycle simulation system is not limited to a stationary type utilization. For example, where a bicycle simulation system is used in a traffic safety classroom held for children at various places, the bicycle simulation system is transported by a transporting vehicle or the like each time the classroom is held or finished. The system must be manually conveyed from the use site to the transporting vehicle. Taking such a use into consideration, the dummy bicycle described in Japanese Patent Publication No. Hei 6-7873 is wholly lifted up and conveyed, which requires labor because the flywheel provided in the dummy bicycle is particularly heavy.
In addition, in the bicycle simulation system, the realism is high if the pedals, a brake lever and a steering handle can be operated in the same manner as in riding a real bicycle. More particularly, the realism is further favorably enhanced if the simulated vehicle velocity can be lowered by operating the brake lever. Further, it is preferable that the same load as in a real bicycle is exerted on the pedals according to the velocity and the acceleration. It is preferable that the feeling of operating the brake lever is as close to that in a real bicycle as possible.
From such a viewpoint, a simulator has been proposed in which a restriction portion formed of an elastic material such as rubber is provided at an end portion of the brake lever. The restriction portion is deformed under an operation of the brake lever so as to make the operating feeling close to that during real cycling. See, for example, Japanese Patent Laid-open No. Hei 11-174944.
In the simulator described in Japanese Patent Laid-open No. Hei 11-174944, the load exerted on the pedals is regulated simply according to a picture on a display, so that the interrelations between the rotation of the pedals, a simulated velocity or acceleration obtained by the rotation, the load exerted on the pedals, and the brake lever operations are not sufficiently taken into account. Thus, the following inconveniences are presumably generated. A time lag may be generated after a brake lever operation and before the start of deceleration, or an appropriate degree of deceleration according to the brake lever operation amount may not be obtained. Furthermore, it is difficult to accurately reproduce the situation in which a high load is exerted in the beginning stage upon the starting and a low load is exerted during constant-velocity running after acceleration.
In addition, in the brake mechanism in the simulator described in Japanese Patent Laid-open No. Hei 11-174944, a stationary elastic material is simply compressed, so that faint vibration of a rotary body transmitted to the brake lever cannot be reproduced. Thus, subtle velocity control through a small brake lever operation is difficult to achieve.